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In the present study, porous commercially pure (CP) Ti samples with different volume fraction of porosities were fabricated using a commercial additive manufacturing technique namely laser engineered net shaping (LENS™). Mechanical behavior of solid and porous samples was evaluated at room temperature under quasi-static compressive loading. Fracture surfaces of the failed samples were analyzed to determine the failure modes. Finite Element (FE) analysis using representative volume element (RVE) model and micro-computed tomography (CT) based model have been performed to understand the deformation behavior of laser deposited solid and porous CP-Ti samples. In vitro cell culture on laser processed porous CP-Ti surfaces showed normal cell proliferation with time, and confirmed non-toxic nature of these samples., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The electrochemical and cellular behavior of commercially pure titanium (CP-Ti) with both ultrafine-grained (UFG) and coarse-grained (CG) microstructure was evaluated in this study. Equal channel angular pressing was used to produce the UFG structure titanium. Polarization and electrochemical impedance tests were carried out in a simulated body fluid (SBF) at 37°C. Cellular behaviors of samples were assessed using fibroblast cells. Results of the investigations illustrate the improvement of both corrosion and biological behavior of UFG CP-Ti in comparison with the CG counterpart., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Commercially pure titanium (CP-Ti) plates were friction stir welded (FSWed) using a welding tool with a tungsten carbide (WC) pin. The bead-on-plate technique was applied to reduce the effects of welding defects, such as incomplete penetration. Whereas many papers have reported on creep studies of CP-Ti as well as on FSW of CP-Ti, no paper has investigated the creep behavior of a CP-Ti FSW'ed joint. Consequently, the current study focuses on this topic. The current paper, which is part of a broader research project, focuses on the metallurgical processes occurring during the creep of a FSW'ed CP-Ti joint at the temperature range of 550-650 °C. Based on the current study and previous results obtained by the authors, it can be concluded that the weld is not the weakest link. In every case, necking and creep fracture occurred in the parent material (PM), rather than either the thermomechanically affected zone (TMAZ) or the stir zone (SZ), indicating that both zones are more creep-resistant than the parent material. Fractography showed that the fracture surface was typical of creep fracture and that the fracture mechanism was microvoid coalescence and also ruled out any preexisting defect. TEM study of broken crept specimens revealed randomly distributed dislocations but no evidence of grain refinement, hence leading to the conclusion that dislocation glide was the dominant creep mechanism. The technological implication of the current study is that the welding process is safe for use as far as its creep properties are concerned. [ABSTRACT FROM AUTHOR]

In this work, the results of an investigation of electron-beam-welded samples of commercially pure titanium (CP-Ti) and the titanium alloy Ti6Al4V (Ti64) using fillers of various beta-stabilizing elements (Nb, V, Cu) are presented. The fillers were in the form of deposited layers on each of the two specimens via DC magnetron sputtering. The specimens were then subjected to electron-beam welding (EBW) under the same technological conditions. The structure of the obtained welded joints was investigated by scanning electron microscopy (SEM). X-ray diffraction (XRD) was used to investigate the phase composition of the fusion zone (FZ). The study of the mechanical properties of the samples was carried out via tensile tests and microhardness measurements. The results showed a different influence of the used fillers on the structure and properties of the obtained joints, and in all cases, the yield strength increased compared to the samples welded using the same technological conditions without the use of filler material. In the case of using Nb and V as a filler, the typical transformation of titanium welds into elongated αTi particles along with α'-Ti martensitic structures was observed. The addition of a Cu filler into the structure of the welds resulted in a unification and refining of the structure of the last, which resulted in the improvement of the mechanical properties of the weld, particularly its ductility, which is a known issue where electron-beam welding is concerned. [ABSTRACT FROM AUTHOR]

The porous hydroxyapatite coatings with a spherical structure were formed on commercially pure titanium (CP-Ti) by the micro-arc oxidation (MAO) in an alkaline electrolyte (hydroxyapatite + 1 M potassium hydroxide) at the applied voltage of 140, 160, 180 V and deposition time of 1 and 2 min. It was determined that by increasing voltage from 140 to 160 V the Ca/P ratio increases from 1.54 to 1.69, i.e., the composition of hydroxyapatite (HA) approaches to the biological one that accelerates formation of the interfacial bond between the implant and bone tissue. It was shown that increasing deposition time from 1 to 2 min at the voltage of 140 V promotes increasing Ca/P ratio. The corrosion resistance of CP-Ti with HA coatings was studied in Ringer's solution at a temperature of 37 °C. The best corrosion protection was observed for the coating deposited at 160 V, 1 min, when the thickness of the coating and HA formation is the highest. [ABSTRACT FROM AUTHOR]

Commercially pure titanium (CP-Ti) plates were friction-stir welded (FSWed) using a welding tool with a tungsten carbide (WC) pin. The bead-on-plate technique was applied to reduce the effects of welding defects, such as incomplete penetration. An X-ray inspection and fractography showed that the FSWed material was free of defects and of WC particles, which may have originated from the welding tool. The appearance of refined equiaxed grains in the thermo-mechanically affected zone (TMAZ) may have been related to dynamic recrystallization (DRX) occurring during the FSW due to the high temperature and intensive plastic deformation involved in the process. Grain refinement, mechanical twinning, and increased dislocation density were detected within the TMAZ, and these microstructural changes were considered to be responsible for the improved mechanical properties of the TMAZ. The TEM study reported in the current paper revealed the presence of nano-sized grains in the FSWed material due to dynamic recrystallization (DRX) occurring during the processing stage. The microstructure obtained during FSW of Ti has been reported in a several publications, yet many discrepancies can be found in these publications. Among these discrepancies are the size and the shape of the grains at the various zones, as well as the presence or non-presence of various zones at the vicinity of the weld. The current study contradicts the argument for correlations between the conditions prevailing at different points across the TMAZ and microstructural changes, which were previously proposed by several researchers. [ABSTRACT FROM AUTHOR]

In the present work, pack carburization with rubberwood charcoal and rubberwood ash at 925 °C for 6, 12, and 24 h was carried out to improve the surface hardness of commercially pure titanium (CP-Ti). X-ray diffraction and energy dispersive spectrometer analyses revealed the formation of titanium carbide (TiC) and the existence of oxygen diffusion in the carburized surface. The surface hardness of most optimized conditions has remarkably increased by 481 % as compared to untreated CP-Ti (from 175 HV to 1016 HV) due to the TiC surface layer, while the hardened oxygen diffusion layer a bout 300 um in depth, as clearly seen in the microhardness profiles is useful for increased load-bearing capacity. Consequently, pack carburization with rubberwood charcoal and rubberwood ash is a promising surface modification technique, which can significantly enhance the surface hardness and increase the loadbearing capacity of CP-Ti for biomedical and tribological applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The passive film formed at 1 V is the densest. • The passive film formed at 1.8 V possessed the strongest capacity to repeal F–. • The average valences were linear with the applied potentials. • N D appeared to be positively correlated with the applied potential. • The change in ICRs was almost proportional to the variations in O2– content. The correlation between applied potentials and the passive films of commercially pure titanium (CP-Ti) in a simulated proton exchange membrane water electrolysis (PEMWE) environment was investigated. In the first passive region, the passive film formed at 1 V exhibited superior overall performance. The values of N D were positively correlated with the applied potentials. The oxygen vacancy diffusivities were determined to be on the order of 10–17 cm2 s−1. The average valences of the passive films were positively linear with the applied potentials. As further increasing the potential, due to the intense OER and consequent growth, the oxide ratios and average valences of the passive films increased. The corrosion induced by accelerated stress cycle (ASC) tests was slight and crystallographically oriented. After increasing the frequency of potential change, the total Ti oxides were slightly less than those of 2.5 V. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to investigate the structural, tribological and electrochemical properties of Ag2O, ZnO, NiO coatings and Ag2O/ZnO/NiO nanocomposite films deposited on commercially pure titanium. Design/methodology/approach: Ceramic thin films (Ag2O, ZnO, NiO coatings and Ag2O/ZnO/NiO nanocomposite film) were deposited on commercially pure titanium (CP-Ti) substrate. Surface characterization of the uncoated and coated samples was made by structural surveys (scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, tribological and corrosion experiments. Findings: Results were indicated that sol-gel coatings improved the wear and corrosion resistance of CP-Ti, and the best results were seen at the nanocomposite coating. It may be attributed to its small grain size, high surface hardness and high film thickness. Originality/value: This study can be a practical reference and offers insight into the influence of nanocomposite ceramic films on the increase of hardness, tribological and corrosion performance. Also, the paper displayed a promising approach to produce Ag2O/ZnO/NiO nanocomposite coating on commercially pure titanium implants for biomedical applications. [ABSTRACT FROM AUTHOR]

Abstract In order to understand the effects of cyclic asymmetry and control mode on low cycle fatigue (LCF) behavior of CP-Ti along rolling direction (RD), symmetrical strain and stress-controlled fatigue tests were conducted in this paper. LCF behavior of CP-Ti along RD under different control modes was systematically compared from the aspects of cyclic response, microstructure evolution and fatigue life with the technique of electron backscatter diffraction (EBSD) and scanning electron microscope (SEM). It was found that cyclic softening resulted by dislocation slip dominates strain-controlled fatigue. On the contrary, cyclic hardening dominates stress-controlled fatigue at high stress amplitude, leading to a higher cyclic stress-strain curve. Owing to asymmetrical hysteresis loop, compressive ratcheting strain is accumulated in stress-controlled LCF test despite of the fully reversed stress cycling. EBSD results show there is a transition of deformation mechanism from dislocation slip to dislocation slip and twinning dominated cyclic deformation with the increase of compressive ratcheting strain. Meanwhile, GOS analysis and SEM observation indicate that the appearance of massive twins results in the heterogeneous plastic deformation and micro-cracks are favorable to be initiated in the twin abundant area. Besides, compressive ratcheting strain has significant effects on fatigue crack growth as the fracture surface presents the serious abrasion of cleavage facets and fatigue striations. Finally, strain-life curves under different control modes are identical, indicating that fatigue life along RD is insensitive to compressive ratcheting strain under the interaction of these factors. [ABSTRACT FROM AUTHOR]

Abstract Commercially pure titanium (Cp-Ti) is commonly used in different applications due to its good structural properties but its low mechanical and tribological properties restrict its usage areas. Therefore, different surface modifications based on TiO 2 formation on material surfaces are applied to enhance surface features of materials. In this study, TiO 2 films were produced on Cp-Ti by sol-gel and successive ionic layer adsorption and reaction (SILAR) methods to compare the effectiveness of these methods. The structural, morphological and mechanical features of TiO 2 films were investigated by XRD, SEM and nano-indentation tester. The tribological features of coatings were characterized by using a pin-on-disk tribotester. The electrochemical behavior of TiO 2 coatings was determined by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analyses. The structural and mechanical analyses showed that sol-gel method caused the formation of more stable and hard film structures with good adhesion in comparison to SILAR method. For that reason, TiO 2 films produced by sol–gel process exhibited better wear and corrosion resistance than the films produced by SILAR. Highlights • TiO 2 films were deposited on Cp-Ti by the sol-gel and SILAR methods. • Corrosion and wear properties of TiO 2 films were investigated. • TiO 2 films by sol-gel showed better wear resistance due to their high hardness. • Corrosion resistance of Cp-Ti improved with TiO 2 films formed by two methods. [ABSTRACT FROM AUTHOR]

In the present paper, the influences of different double layer on wear and scratch performances of commercially pure Titanium (CP-Ti) were investigated. TiO2/SiO2 and SiO2/TiO2 double layer coatings were deposited on CP-Ti by sol-gel dip coating process and calcined at 750C. The phase structure, cross-sectional morphology, composition, wear track morphologies, adhesion properties, hardness and roughness of uncoated and coated samples were characterized with X-ray diffraction, scanning electron microscopy (SEM), nano-indentation technique, scratch tester and 3D profilometer. Also, the tribological performances of all samples were investigated by a pin-on-disc tribo-tester against Al2O3 ball. Results showed that hardness, elastic modulus and adhesion resistance of double layer coated samples were higher than untreated CP-Ti. It was found that these properties of TiO2/SiO2 double layer coatings have higher than SiO2/TiO2 double layer coating. Additionally, the lowest friction coefficient and wear rates were obtained from TiO2/SiO2 double layer coatings. Therefore, it was seen that phase structure, hardness and film adhesion are important factors on the tribological properties of double layer coatings. [ABSTRACT FROM AUTHOR]

The evolution of microstructure and texture of commercially pure titanium (CP-Ti) developed by unidirectional rolling (UDR) and multi-step cross rolling (MSCR) followed by annealing treatment at different temperatures was investigated by X-ray bulk texture measurement and electron backscatter diffraction (EBSD) technique. Recrystallisation was complete at about 873 K for both UDR and MSCR samples. In UDR mode, the TD-split type deformation texture remain unchanged whereas in MSCR mode, near basal deformation texture transformed to RD split type basal texture after annealing. This has been attributed to the non-oriented nucleation of recrystallised grains and growth of (0002)< 11 2 ¯ 0 > (major) texture component of the deformed sample by consuming (0002)< 10 1 ¯ 0 > (minor) texture component in UDR. Whereas in MSCR sample, oriented nucleation of (0002)< 10 1 ¯ 0 > and (0002)< 11 2 ¯ 0 > basal texture components occur which compete at the growth stage leading to weak recrystallisation texture compared to UDR. The distinct texture evolution with similar grain size after recrystallisation leads to similar hardness for UDR and MSCR samples. [ABSTRACT FROM AUTHOR]

The aim of the present work is to investigate the effects of prestrain and subsequent annealing on tensile properties of commercial pure titanium (CP-Ti). According to tensile test results, yield strength and ultimate tensile strength increase with the increase of prestrain. Elongation and uniform strain decrease linearly with prestrain. In the case of prestrain that is higher than 3.5%, the macro-yield of specimens changes from gradual yielding to discontinuous yielding. It is supposed that considerable numbers of dislocations introduced into the material lead to the appearance of yield plateau. The quantitative analysis of the contribution of dislocation hardening to the strain hardening shows that dislocation-associated mechanisms play an important role in strain hardening. Moreover, a modified Fields-Backofen model is proposed to predict the flow stress of prestrained CP-Ti at different strain rates. Both strain rate sensitivity and strain hardening exponent decrease with prestrain. Fracture surfaces of the specimens show that fracture mechanism of all tested specimens is dimple fracture. The more ductile deformation in prestrained CP-Ti after annealing indicates that its ductility is improved by annealing. [ABSTRACT FROM AUTHOR]

The present investigation reports the effect of different electrolyte additives on in-vitro corrosion behavior of the plasma electrolytic oxidation (PEO) coatings formed on commercially pure titanium (Cp-Ti). PEO coatings were produced using a pulsed DC power source at a constant current density of 70 mA/cm 2 and a treatment time of 8 min. Different coatings were developed with different additives (sodium sulfate, Tris, di-ammonium hydrogen phosphate and ammonium acetate) added to a base electrolyte consisting of TSOP and KOH. PEO coatings were characterized for phase composition, elemental composition, surface and cross-sectional microstructure, corrosion behavior, apatite forming ability and osteoblast cell adhesion. The corrosion resistance of the developed oxide coatings was evaluated in a Kokubo simulated body fluid (SBF) by potentiodynamic polarization test and EIS study. The in-vitro bioactivity of all the PEO coatings and the untreated substrate was studied by soaking the samples in an SBF environment for 21 days. The TiO 2 layer formed in phosphate, sulfate and nitrite containing electrolyte highly enhances the apatite formation in SBF. An in-vitro cell adhesion test was performed on all coatings using human osteosarcoma cells for 48 h. SEM images of cell adhesion test showed that human osteosarcoma cells were well adhered and spread on all PEO treated samples. Among all the additives, Tris has provided higher corrosion resistance in the SBF environment with good apatite forming ability and osteoblast cell adhesion. [ABSTRACT FROM AUTHOR]

In this study, the criteria for { 11 2 ‾ 2 } compression twinning in commercially pure titanium (CP–Ti) were investigated by uniaxial tensile tests, crystal plasticity finite element (CPFE) analyses, and slip operation factor (SOF) calculations. First, the aggregates of the [0001] axes of CP-Ti were inclined in the rolling direction (RD), implying its RD-split texture. The development of the crystal orientation distribution with deformation was observed by electron back-scattered diffraction (EBSD). Active slip systems were identified by kernel average misorientation (KAM) and intergranular misorientation axis (IGMA) analyses. The dominant slip system was prismatic , whereas the non-prismatic slip systems were activated near the grain boundary. Active twin systems were also identified by the rotation angles of the [0001] axes between the twin and matrix. The dominant active twin system was the { 11 2 ‾ 2 } compression twin, although a uniaxial tensile load was applied. Second, the positions of { 11 2 ‾ 2 } twinning were predicted by CPFE analysis using the resolved shear stress (RSS) criterion while considering plastic deformation. SOF analysis was also employed for the prediction. The CPFE and SOF analyses yielded almost the same level of prediction accuracy. However, these calculations do not completely predict the twinning positions. Finally, the criteria for { 11 2 ‾ 2 } twinning were discussed, and it was revealed that hydrostatic pressure and RSS are possible criteria for { 11 2 ‾ 2 } twinning in the continuum model. [Display omitted] • { 11 2 ‾ 2 } compression twinning was the dominant system under a uniaxial tensile test of CP-Ti with split texture. • Deformation in the microstructure was reproduced by crystal plasticity analyses and slip operation factor calculations. • Criterion using hydrostatic pressure and resolved shear stress helped predict the twinning positions with high accuracy. [ABSTRACT FROM AUTHOR]

Titanium (Ti) and its alloys may be processed via advanced powder manufacturing routes such as additive layer manufacturing (or 3D printing) or metal injection moulding. This field is receiving increased attention from various manufacturing sectors including the medical devices sector. It is possible that advanced manufacturing techniques could replace the machining or casting of metal alloys in the manufacture of devices because of associated advantages that include design flexibility, reduced processing costs, reduced waste, and the opportunity to more easily manufacture complex or custom-shaped implants. The emerging advanced manufacturing approaches of metal injection moulding and additive layer manufacturing are receiving particular attention from the implant fabrication industry because they could overcome some of the difficulties associated with traditional implant fabrication techniques such as titanium casting. Using advanced manufacturing, it is also possible to produce more complex porous structures with improved mechanical performance, potentially matching the modulus of elasticity of local bone. While the economic and engineering potential of advanced manufacturing for the manufacture of musculo-skeletal implants is therefore clear, the impact on the biocompatibility of the materials has been less investigated. In this review, the capabilities of advanced powder manufacturing routes in producing components that are suitable for biomedical implant applications are assessed with emphasis placed on surface finishes and porous structures. Given that biocompatibility and host bone response are critical determinants of clinical performance, published studies of in vitro and in vivo research have been considered carefully. The review concludes with a future outlook on advanced Ti production for biomedical implants using powder metallurgy. [ABSTRACT FROM AUTHOR]

Abstract: The goal of this study was to evaluate the biocompatibility of newly developed Zr61Ti2Cu25Al12 metallic glass (denoted ZT1) and its parallel material, commercially pure titanium (CP-Ti), as dental implants. To this end, we evaluated their cytotoxicity in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo by performing an oral mucosa irritation test in hamsters. Specifically, cytotoxicity was determined in HUVECs by evaluating their cell morphology using scanning electron microscopy (SEM) and their cell viability using CCK-8 assays. Moreover, we examined the mRNA levels of vascular endothelial growth factor and von Willebrand factor by quantitative PCR (qPCR). In the early stages of proliferation and differentiation, no differences were observed between HUVECs inoculated on ZT1 compared to those on CP-Ti. However, in the later stages of proliferation and differentiation, the HUVECs inoculated on ZT1 were significantly better than the cells cultured on CP-Ti. In the oral mucosa irritation test, we sutured sample discs into the cheek pouch of hamsters. After 2, 3, and 4weeks, we harvested the corresponding mucosal tissues, stained them with hematoxylin and eosin, obtained blood samples for biochemical analysis, and finally, observed the topography of the sample discs by SEM. Immunohistochemistry and hematology analyses showed no differences in the biocompatibility of ZT1 and CP-Ti, and neither of these compounds caused irritation of the mucosa. In addition, SEM images showed that no pitting occurred on the sample discs. Together, these data indicate that ZT1 may be a good candidate for dental implants and should be further studied. [Copyright &y& Elsevier]

Abstract: Commercially pure titanium (CP-Ti) is commonly used as an implant material especially for orthopedic and dental treatments in biomedical applications. This material shows insufficient tribological properties. Some surface treatments were applied on surface CP-Ti in order to improve tribological properties of the CP-Ti. Among these techniques, sol–gel coating process was used for this purpose. In this study, CP-Ti was coated by TiO2 film with sol–gel dip coating process. Coated samples were calcined at the various temperatures. The effects of calcination temperature on the wear performance of the coated films were observed. It was observed that the hardness, elastic modulus, surface roughness, friction coefficient and wear resistance values of coated samples were higher than the uncoated CP-Ti values. Also, these properties of coated samples increased with increasing of calcination temperature. The intensity of the rutile-TiO2 phase increased with the calcination temperatures. It was determined that rutile-TiO2 structure showed self-lubrication like behavior. The best tribological properties were obtained from the sample calcinated at 900°C. [Copyright &y& Elsevier]

Abstract: Equal channel angular pressing (ECAP) was conducted at 250°C on commercial purity titanium up to 10 passes. An ultrafine-grained microstructure with a mean grain size of about 183nm was obtained. The evolution of stored energy and recrystallization temperature was studied by differential scanning calorimetry. The activation energy involved in the recrystallization process was also determined. The results show that with increase of ECAP passes up to 6 the recrystallization temperature increases. Also, it is seen that with increasing ECAP passes up to 8 the stored energy increases, beyond which it saturates at a value of about 58J/mol. For the recrystallization of 10 passes ECAP-ed samples, average activation energy of about 342kJ/mol was determined. [Copyright &y& Elsevier]

Abstract: Titanium exhibits properties that are excellent for various applications but the processing routes remain expensive and difficult. Metal injection moulding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. In this study, the commercially pure (CP-Ti) powder was subjected to metal injection moulding studies in order to investigate its suitability for biomedical applications. The CP-Ti with powder size of sub 45μm was mixed with a binder which consists of a water soluble component, injection moulded and then sintered. The mechanical and impurity level properties of the final components were then determined and found to be within ASTM Grade 2 (ASTM F67) specifications for titanium. The debinding mechanisms, kinetics and chemical reactions are analysed and discussed in detail in this study. [Copyright &y& Elsevier]

Abstract: The suppressing effect of ambient-temperature creep of CP-Ti by cold-rolling was reported. Annealed plates of CP-Ti grade 2 were cold-rolled with thickness reductions, and then creep tests under the applied stresses of 0.6–0.9σ 0.2 were performed at ambient temperature. With increasing the thickness reduction, the twin, dislocation density and σ 0.2 were found to increase. At the same time, the steady-state creep rates under the applied stress for constant σ/σ 0.2 were decreased. The cold-rolled sample with 20% thickness reduction was then annealed at 813K for 2400s to decrease only the dislocation density. After the annealing, the steady-state creep rate remained constant, suggesting that the reduction of the steady-state creep is associated with the increasing twin density. [Copyright &y& Elsevier]

[Display omitted] • Developed dual-textured Ti extrudates via utilizing the β transus in CP-Ti. • Revealed the <0001>//ED and <1011>//ED texture on the firstly extruded portion and <1010>//ED texture on the rest extrudate. • Rationalized the formation mechanism of this novel dual-textured microstructure. • Established the correlation between elemental inhomogeneity and mechanical property deviation along the Ti extrudates. In contrast with titanium (Ti) alloys, the α+β region for commercially pure Ti is neglectable. Therefore, its β transus (T β) can be regarded as a watershed for β-Ti and α-Ti. Utilizing this characteristic, we fabricated dual-textured Ti extrudates through a powder metallurgy route via manipulating the hot extrusion temperature. The crystallographic texture along extrusion direction (ED) was analyzed. Different from the sole <1010>//ED texture throughout the entire extrudate in previous studies, our extrudates exhibited unique dual-textured microstructure. The firstly extruded portion manifested <0001>//ED and <1011>//ED, whereas the rest extrudate displayed <1010>//ED. This was attributed to the realtime extrusion temperature of each location in comparison with T β. On the other hand, the last portion of the extrudate contained much more interstitial nitrogen and oxygen, which led to extremely high strength via solid solution strengthening. This was resulted from a combination effect of diffusion-controlled element absorbing and material flow during extrusion. Our findings may open up a new direction in developing high-performance materials with variable microstructure and mechanical properties for medical applications like neoarthrosis. [ABSTRACT FROM AUTHOR]

In this study, the surface of commercially pure titanium (Cp-Ti) was covered by a 21–95 µm-thick aluminum oxide layer using plasma electrolytic oxidation. Coating characterization revealed the formation of nodular and granular α- and γ-Al2O3 phases with minor amounts of TiAl2O5 and Na2Ti4O9 which yielded a maximum 49.0 GPa hardness and 50 N adhesive critical load. The corrosion resistance behavior in 3.5 wt.% NaCl solution of all plasma electrolytic oxidation (PEO) coatings was found to be two orders of magnitude higher compared to bare Ti substrate. [ABSTRACT FROM AUTHOR]

Titanium has been increasingly applied to dental prostheses because of its biocompatibility. However, application remains limited, due to the low strength and poor wear resistance of unalloyed titanium. The purpose of this study is to evaluate the wear resistance of high-strength Ti–6Al–7Nb alloy castings for dental application. Test specimens were cast from commercially pure titanium (CP-Ti grades 2 and 3) and Ti–6Al–7Nb alloy ingots, and subjected to a wear test simulating the occlusal loading pattern. Wear resistance was evaluated by the weight loss during the test. Ti–6Al–7Nb alloy was found to exhibit lower weight loss than CP-Ti. Moreover, scanning electron microscopic (SEM) observation after the test revealed that the worn surface of Ti–6Al–7Nb alloy is much smoother than that of CP-Ti. These results indicate that Ti–6Al–7Nb alloy castings can be used to produce dental prostheses of improved wear resistance and mechanical strength. [Copyright &y& Elsevier]

Understanding of the deformation micro-mechanism as a function of grain orientation during cyclic loading is of significant importance to have failure safe design of structural components made of commercially pure titanium (CP-Ti). The evolution of deformation microstructure and texture of commercially pure titanium samples with prismatic-pyramidal (orientation A) and near basal (orientation B) as initial texture along the loading direction has been investigated during load reversal at ±8% and ± 12% strain using in-situ synchrotron X-ray diffraction. The synchrotron X-ray diffraction results have been further complemented with Elastic-Plastic Self-Consistent (EPSC) simulation of the texture data and ex-situ Electron backscatter diffraction (EBSD) scan taken at the same region. Orientation A showed partially reversible texture whereas orientation B showed non-reversible texture with mechanical reversibility. The partial textural reversibility has been attributed to the prism to basal slip transition which toggles the c-axis between the normal and transverse direction during the tension-compression cycle. With an increase in strain from 8 to 12%, microstrain and dislocation density in the basal plane of orientation A decreases sharply. On the other hand, for the same level of strain in orientation B, microstrain increases but the dislocation density of basal plane shows insignificant change. The crystal orientation map obtained from ex-situ EBSD of deformed microstructure complements to the fact indicating, with increase in strain, deformation of basal oriented grains show non-Schmid behaviour of contraction twin propagation due to local strain incompatibility in orientation A. On the other hand, the prism oriented grains of orientation B have mostly deformed by extension twinning, which reorients them towards basal orientation. The deformation proceeds by lateral thickening of twins due to the lower elastic stiffness of the twinned region compared to the grain matrix. The extension twin boundaries get converted to contraction twin boundaries at higher strain during load reversal. • Evolution of orientation specific deformation microstructure during load reversal • Role of prism to basal slip transition in partial textural reversibility • Non-Schmid behaviour of twin propagation during slip transition • Correlation of twin thickening and twin/matrix elastic stiffness difference [ABSTRACT FROM AUTHOR]